Search found 2753 matches

by haklesup
Fri Jun 14, 2019 4:51 pm
Forum: General Discussion
Topic: Advice on power bank voltages/power
Replies: 7
Views: 359

Re: Advice on power bank voltages/power

Parasitic Series resistance, I've seen it toast and once melt a connector body down to a puddle. I recently cleared a fault on one piece of equipment where low voltage on logic 5V caused by connector series resistance dropped it so low (3.4V), the PC couldn't communicate with it. Yes, anything highe...
by haklesup
Fri Jun 14, 2019 12:11 pm
Forum: General Discussion
Topic: Mini amp circuit
Replies: 147
Views: 204558

Re: Mini amp circuit

scoping those nodes, you are really looking at the current flowing through the base bias resistors, Since the PN junction (B-E) of the NPN transistor and the NP junction (B-E also) of the PNP are non linear, the current flow into the bases is non linear (due to the diode characteristic of the B-E ju...
by haklesup
Mon Jun 10, 2019 11:58 am
Forum: General Discussion
Topic: Crazy Phone issues here..
Replies: 11
Views: 353

Re: Crazy Phone issues here..

Well, Once I paid the city garbage bill to the city water department because they have similar names and I wasn't wearing glasses while operating an online banking session. I didn't figure it out until the late notice showed up. It happens to the best of us. I think not all cities have exactly the s...
by haklesup
Fri Jun 07, 2019 11:17 am
Forum: General Discussion
Topic: Crazy Phone issues here..
Replies: 11
Views: 353

Re: Crazy Phone issues here..

Did you pay your phone bill? Normally when a caller gets a not in service recording the line is unpaid and intentionally disconnected. I think you need to call your phone company (on your cell phone) to find out why. Busy on your end implies the wire is at least connected to the system and not damag...
by haklesup
Thu Jun 06, 2019 1:05 pm
Forum: General Discussion
Topic: Something Wrong with Coupling Capacitor
Replies: 10
Views: 817

Re: Something Wrong with Coupling Capacitor

A block diagram is a simplified schematic where subcircuits or whole modules are represented by squares with labels and lines connect the blocks representing the important signals. you can find many examples searching on "electronic block diagram audio" its kind of like a flow chart.
by haklesup
Thu Jun 06, 2019 1:02 pm
Forum: General Discussion
Topic: 1N457 need equivalent
Replies: 12
Views: 2104

Re: 1N457 need equivalent

Digikey was a good website 11 years ago, its even better now. As for support, expect limits, they are not design engineers, they can cross reference and help you find or buy stuff but they probably cannot recommend part numbers based on application or design questions. BTW, what kind of reviews on E...
by haklesup
Thu May 30, 2019 12:33 pm
Forum: General Discussion
Topic: Help with a circuit again
Replies: 5
Views: 271

Re: Help with a circuit again

I guess that changes the trigger point from the falling edge to the rising edge of the outside rail. you may need to change the values of R3 and R4 if the bias current to turn off the Darlington PNP is different.
by haklesup
Thu May 30, 2019 12:25 pm
Forum: General Discussion
Topic: cutoff circuit for battery
Replies: 2
Views: 133

Re: cutoff circuit for battery

for the 12V application, there are tons of relay controlled modules on ebay but they consume a fair amount of current on their own especially the relay based ones. I tried to implement some in a car to power off the audio amps when running on battery if it got too low but they tend to kill the batte...
by haklesup
Tue May 28, 2019 4:19 pm
Forum: General Discussion
Topic: Technology Backfire?
Replies: 38
Views: 1905

Re: Technology Backfire?

the amount of energy transmitted at 60Hz from a high tension wire a hundred or so feet away would not be that large (his could probably had more current behind it than the open probe) but if your friend placed the coils on a windmill type thing, he could have increased the flux lines that were cut a...
by haklesup
Tue May 28, 2019 12:57 pm
Forum: General Discussion
Topic: Question About Computer ATX PSU
Replies: 3
Views: 189

Re: Question About Computer ATX PSU

For the most part "Auto Power off" is controlled either by the OS or by BIOS, all you can do in hardware is disable the ability of the MB to turn off the PSU so you can keep something else alive that you can't keep powered with the low current 5V that normally stays on all the time. Check your BOIS ...
by haklesup
Mon May 13, 2019 3:53 pm
Forum: General Discussion
Topic: CNC Router anyone?
Replies: 5
Views: 270

Re: CNC Router anyone?

CNC is more of a Mechanical engineering thing than Electronics but I'm sure you will find some well focused groups out there if you look. I know there are some interesting CNC controller electronics on ebay and the likes that can be used as the brains of the CNC or 3D printer (similar to CNC but add...
by haklesup
Mon May 13, 2019 3:38 pm
Forum: General Discussion
Topic: Gain block question
Replies: 1
Views: 131

Re: Gain block question

you'll never get High impedance using BJT and not good range if you are controlling the base with voltage (since it is a current controlled terminal, you need series resistance to turn that into a controllable current and it still will not be linear because a diode junction is not). I think you will...
by haklesup
Mon May 13, 2019 3:23 pm
Forum: General Discussion
Topic: [18650] rechargeable battery + super capacitor
Replies: 7
Views: 250

Re: [18650] rechargeable battery + super capacitor

Those Vishay super caps look like a good match but read the datasheet carefully, the only spec that might get in your way is the DC ESR which is as high as 70 ohms for some models. This will limit the discharge current you can effectively use by lowering the effective voltage (if I understand that c...
by haklesup
Mon May 13, 2019 3:01 pm
Forum: General Discussion
Topic: jack Question
Replies: 3
Views: 250

Re: jack Question

This is the only one I found. https://www.digikey.com/products/en/connectors-interconnects/barrel-audio-connectors/434?k=&pkeyword=&sv=0&pv272=74&sf=0&FV=ffec10de&quantity=&ColumnSort=0&page=1&pageSize=25 I assume 3 are for the audio and also 2 N.C switches. The one above looks like maybe 1 N.O SPST...
by haklesup
Fri May 10, 2019 10:40 am
Forum: General Discussion
Topic: [18650] rechargeable battery + super capacitor
Replies: 7
Views: 250

Re: [18650] rechargeable battery + super capacitor

I don't think you can fit a capacitor big enough in your pocket. Assuming you don't want to engineer a sleep mode or its not paratactical, then a secondary external battery hookup so you can temporarily power it externally while you swap the internal battery seems like the simplest approach. If you ...